A conventional known active mixer circuit is typically formed using a diode, a bipolar junction transistor (BJT), or a GaAs field effect transistor (FET). To combine both RF and LO signals for mixing, inputs must first be combined using a summation circuit. Conventional mixer circuits are reviewed, for example, in an article by A. M Pavio et al. entitled "Double balanced mixers using active and passive techniques", in IEEE Trans. on Microwave Theory and Techniques MTT Vol. 36, no. 12 (Dec. 1988); and in a book by S. Maas entitled "Microwave Mixers" published by Artech House, Norwood Mass. (1986). Of course, each active element in a circuit contributes noise, and ideally a simplified circuit with fewer components is sought.
Thus, the present invention seeks to provide an integrated circuit with reduced noise characteristics and with particular application for mixing signals and modulating high frequency signals in a simple manner with minimal components.
A four or five terminal semiconductor device taking the form of a merged field effect/lateral bipolar junction transistor, which is termed a Gate Controlled Lateral Bipolar Junction Transistor, GCLBJT is described in copending U.S. patent application to Malhi et. al., having two co-inventors in common with those of present invention, which relates to an application of this device.